Needle insertion to access a target region in a subject's tissues, such as a lesion, for instance, is a common clinical procedure, carried out in order to perform procedures such as a tissue biopsy, or to perform a minor surgical procedure, or for the insertion of a diagnostic or therapeutic probe. Currently, guidance of a surgical needle insertion into a tissue to a target lesion can be performed manually under ultrasound (US) guidance, by observation of the lesion in the ultrasound image and by estimation of the correct insertion point and angle to be used in order to access the lesion with the needle. The accuracy of this procedure is highly dependent upon the skill of the doctor performing the procedure. Computer assisted guided insertion can also be performed using ultrasound imaging, by using a navigation system in order to track both the position of the ultrasound probe, and the position of the tool guide or the tool itself. The navigation system can then ensure that when the ultrasound probe is held at such an angle that the target lesion falls in a predefined position on the screen, the tool guide or the tool can be directed, either manually or by a robot to pass through the position of the lesion. Use of a virtual trajectory of the tool path, or a virtual image of the tip of the needle, projected onto the ultrasound image, can make this procedure accurate and simple for the doctor to execute. However, this system requires a navigation system which tracks and correlates between two distinct bodies, and the system is therefore generally complex and costly.
There therefore exists a need for a ultrasound guidance system, which enables access to a target point within the subject's tissue, and which overcomes at least some of the disadvantages of prior art systems and methods.
The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety.